JPH09156792A - Separating mechanism for automatic document conveying device and manufacture of separating member to be used in separating mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent dirt on documents in separating without deteriorating separating performance and feeding performance. SOLUTION: A separating mechanism 7 is so constituted as to separating and feeding a plurality of documents one by one by making a document 2 pass between a paper sheet feeding roll 8 and a separating member 9 to be brought in contact with the paper sheet feeding roll 8. The separating member 9 is formed of a material taking polyurethane as the base, has the coefficient of surface friction required for separating the documents, and has smoothness like mirror finishing on the front surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic document feeder used in a copying machine or a facsimile machine,
In particular, the present invention relates to a separating mechanism for separating a plurality of stacked originals one by one and sending the separated originals, and a manufacturing method of a separating member used in the separating mechanism.

[0002]

2. Description of the Related Art For example, in an automatic document feeder of a copying machine, a bundle of documents is stacked on a document tray, and the lowest document in the document stack is sequentially sorted and sent out. In this automatic document feeder, a roll or a pad is used as a separating member in order to separate and feed the documents one by one. The separating member is provided so as to face the rotationally driven paper feed roll, and when the document passes between the paper roll and the separating member, the surface of the document is rubbed to prevent double feeding. There is. The surface of the separating member is formed of a material having a large friction coefficient so that a sufficient frictional force can be obtained.

When the original is separated by the separating member, the surface of the original is rubbed by the separating member. For example, in the case of a pencil-written original, a part of the pencil dust adhering to the surface of the original is scraped off. The document may adhere to other places and stain the document.

More specifically, the conventional separating member is formed of a material having abrasion resistance so that a friction coefficient of 0.8 to 1.0 can be stably obtained with respect to paper. , Its surface is polished, and the unevenness of the polishing mesh (1
0 μm), and when a pencil-written original is separated, the unevenness of the surface of the separating member is larger than the particle size (8 to 30 μm) of the pencil powder on the surface of the original, so the pencil powder is scraped off. However, there is a problem that the surface of the original becomes dirty.

As a countermeasure against such inconvenience, Japanese Unexamined Patent Publication No.
No. 79938, a member having a low surface friction coefficient is used as a separating member, or as described in JP-A-61-86329, a pair of rollers forming the separating member is used. It is known that a collar portion is provided so that the collar portions overlap each other, and the amount of overlap can be adjusted. Moreover, the force of pressing the separating member is reduced, and the area of pressing is increased.

[0006]

However, in the above-mentioned measures, there is a problem that the sorting performance is lowered and the originals are double-fed, or the feeding performance is lowered and misfeed occurs. There were many

[0007] Therefore, an object of the present invention is to prevent the original document from being soiled at the time of sorting, without lowering the sorting performance or the feeding performance.

[0008]

SUMMARY OF THE INVENTION According to the present invention, an automatic document is fed out by feeding a plurality of documents one by one by passing the document between a paper feed roll and a separating member pressed against the paper feed roll. In the separating mechanism of the conveying device, the separating member is molded from a material based on polyurethane, has a surface friction coefficient necessary for separating an original, and has a smooth surface of a mirror finish. It is characterized by

The surface roughness of the separating member is 8 μm.
It is characterized by the following.

Further, according to the present invention, a separating mechanism of an automatic document conveying device which separates a plurality of originals one by one by feeding the originals between a paper feeding roll and a separating member pressed against the paper feeding roll. In the method for manufacturing the separating member used in, the inside of the mold for molding the separating member is made of a material having water repellency and good releasability, and its inner peripheral surface has a smoothness of a mirror finish. The present invention is characterized in that the existing collar is mounted, and the inside of the collar is filled with a material based on polyurethane to be molded.

Examples of the material having water repellency and good releasability include rubber materials such as silicone rubber and fluororubber, resin materials such as polyolefin resin, polyacetal resin, polyamide resin, and silicone resin. , A silicone-based oil, a fluorine-based resin, a resin material containing a water-repellent component such as a fluorine-based oil, or a rubber material.

[0012]

1 is a principle view showing the overall structure of an automatic document feeder to which the present invention is applied. FIG.
FIG. 2 is an enlarged schematic view showing the vicinity of a sorting mechanism of the automatic document feeder shown in FIG. 1.

The automatic document feeder is provided to openably and closably cover the platen glass 1 of a document reading device (not shown) for scanning and reading a document. A bundle of originals 2 is placed on an original placing tray (not shown), and the lowermost original is delivered by the delivery roll 3. At this time, as shown in FIG. 2, the uppermost original of the bundle of originals 2 is pressed by the feeding roll pressing member 4.
Further, the presence or absence of a document on the document placing tray is detected by the document set sensor 5.

The document fed by the feeding roll 3 advances along the path A along the paper chute 6 and is separated by the separating mechanism 7.
Leads to. The separating mechanism 7 is composed of a paper feed roll 8 which is rotationally driven in the direction of arrow P by a drive mechanism (not shown), and a roll-shaped separating member 9 which is provided in pressure contact with the paper feed roll 8. . The separating member 9 is attached to the fixed shaft via a one-way clutch (not shown),
Although it does not rotate in the paper transport direction, it can rotate in the direction opposite to the paper transport direction.

As shown in FIG. 2, a plurality of originals 2 are fed out by the feeding roll 3, and when the bundle of originals reaches the pressure contact portion between the paper feed roll 8 and the separating member 9, that is, the nip portion, the paper is fed. The paper roll 8 conveys the lowest document in order. The coefficient of friction of the paper feed roll 8 and the coefficient of friction of the separation member 9 are selected to be larger than the friction coefficient of the document, and the coefficient of friction of the paper supply roll 8 is selected to be larger than the friction coefficient of the separation member 9. . For example, the coefficient of friction of the paper feed roll 8 is 1.5 to 2.0, and the coefficient of friction of the separating member 9 is 0.
8 to 1.0, and the friction coefficient of the document is 0.3 to 0.5.

Here, for example, when two originals enter the nip portion, the frictional force between the separating member 9 and the original and the paper feed roll 8 and the original are more than the frictional force between the originals. Since the frictional force of the original is larger, a slip occurs between two overlapping originals, and only the original of the two originals that comes into contact with the paper feed roll 8 is conveyed and the original that comes into contact with the separating member 9 is conveyed. Remains stopped. When the number of originals in the nip portion becomes one, the frictional force between the paper feed roll 8 and the original is larger than the frictional force between the separating member 9 and the original.
And a document is slipped, and this one document is conveyed by the paper feed roll 8. In this way, the originals are sorted and double feeding is prevented.

Documents 2 separated one by one by the separation mechanism 7.
Is conveyed along the path B and is conveyed onto the platen glass 1 by a pair of conveying rolls including a conveying roll 10a and a pinch roll 10b. The original 2 loaded on the platen glass 1 is transported on the platen glass 1 by the transport belt and placed at a predetermined original reading position. In this state,
The image of the original is read from the lower side of the platen glass 1.

In the case of a single-sided original, the original after the reading is carried out by the conveyor belt device 11 in the direction of arrow Q and carried out to a not-shown original carrying-out tray.

In the case of a double-sided original, the original after the first side reading is carried out in the direction of arrow R by the carrying belt device 11, and is carried along the U-shaped paper chute 12 by the carrying roll pairs 13a and 13b. It is conveyed by the roll pair 14a, 14b and advances along the route, and further, the conveyance roll pair 10a, 1
0b, and the second surface of the platen glass 1 is conveyed downward. After that, the second surface is read in the same manner as the first surface. The original after the double-sided reading is carried out in the direction of arrow Q by the conveyor belt device 11 and is carried out to a not-illustrated original carry-out tray.

In this embodiment, the separating member 9 described above is used.
The surface of is made a mirror surface state with substantially no unevenness. For example, the surface roughness is 8 μm or less, preferably 5 μm or less, and more preferably 1 μm or less. The surface roughness referred to here means the difference in height of the unevenness in the vertical direction.

In the present embodiment, the reason why the surface roughness of the separating member 9 is 8 μm or less is as follows. As described above, in the case of a pencil-written original, the particle size of the pencil powder attached to the surface of the paper is 8 to 30 μm, but as a result of various experiments, the roughness of the surface of the separating member 9 is It has been found that when the particle size is larger than the particle size of the powder, the unevenness of the surface of the separating member 9 increases the extent to which the particles of the pencil powder are scraped off. Therefore, in this embodiment, the roughness of the surface of the separating member 9 is set to be smaller than 8 μm, which is the minimum particle diameter of pencil powder. It should be noted that, according to the experiment, even if the surface roughness is about 1 μm in the initial state, it is recognized that the surface roughness is about 4 μm due to abrasion. Therefore, the surface roughness should be as small as possible. Is desirable. in this way,
By making the surface of the separating member 9 a mirror surface state, the unevenness of the surface of the separating member 9 becomes smaller than the particle size (8 to 30 μm) of the pencil powder, so that the separating member 9 can scrape the pencil powder on the original. Therefore, the pencil manuscript does not get dirty.

An example of a method for manufacturing the separating member 9 having a mirror surface is shown below. FIG. 3 is an explanatory diagram for explaining the method for manufacturing the separating member 9. Similarly, an annular collar 16 is removably fitted inside a die 15 having a cylindrical cavity made of a material having sufficient strength against a molding pressure. The collar 16 is manufactured by molding a material having water repellency and good releasability. This color 1
The inner surface of 6 is mirror-finished with a surface roughness of 1 μm or less. As the material having water repellency and good releasability, a rubber material such as silicone rubber or fluororubber, or a resin material such as a polyolefin resin or a polyacetal resin,
Alternatively, either a resin material or a rubber material containing a water-repellent component such as silicone resin, silicone oil, fluorine resin, or fluorine oil can be used.

Next, a material based on polyurethane is poured into the inside of the collar 16 and molded. The pressure generated during molding is received by the mold 15 via the collar 16, so that the collar 16 is not deformed.

Here, as the polyurethane, a two-liquid mixed casting type polyurethane material, millable
In general, polyurethane materials such as le) type polyurethane material and thermoplastic type polyurethane material can be used. Examples of the cast polyurethane material include Cyanaprene A- manufactured by Takeda Pharmaceutical Co., Ltd.
9QM can be used, and as the millable type polyurethane material, for example, Spamin 640S manufactured by Sumitomo Bayer Urethane Co., Ltd. can be used.
As the thermoplastic polyurethane material, for example, E390 manufactured by Nippon Miractolan Co., Ltd. can be used.

In the case of cast-type polyurethane materials, approximately 100% of the composition is polyurethane. In the case of a millable type polyurethane material, up to about 50% of a reinforcing agent (filler) is added, but the rest of the composition is almost polyurethane. In the case of thermoplastic type polyurethane materials, almost all are polyurethane. From the viewpoint of abrasion resistance, cast type and millable type are preferable.

Although not shown, a cylindrical mold corresponding to the fixed shaft of the separating member 9 is arranged on the central axis of the collar 16. Alternatively, polyurethane may be directly filled between the fixed shaft and the collar 16.

In this embodiment, polyurethane is used as the material of the separating member 9 for the following reason.

Generally, silicone rubber or polyurethane is used as the material for the separating member of the separating mechanism of the automatic document feeder. Silicone rubber excels in stability, and polyurethane excels in abrasion resistance. When an experiment was conducted with the separating member having the surface of silicon rubber as the mirror surface, the pencil-written original was contaminated when 20,000 originals were conveyed. On the other hand, when a separating member was constructed with the surface of polyurethane as a mirror surface and an experiment was conducted, a result was obtained that the pencil-written original did not become dirty even when 50,000 to 100,000 originals were conveyed. It is considered that this is because the abrasion resistance of polyurethane is excellent and the mirror surface formed first is maintained for a long period of time.
For this reason, in the present embodiment, the separating member 9
Polyurethane is used as the material.

Further, even when the surface of the separating member is a mirror surface, a polyurethane of a kind that can obtain a friction coefficient of 0.8 to 1.0, which is similar to that of the conventional separating member, is selected and used.

Next, the roll-shaped polyurethane is removed from the collar to obtain the outer peripheral layer 9a of the separating member 9. At this time, since the collar is made of a material having water repellency and good releasability, the separating member 9 can be removed from the collar without using a conventionally required release agent. The mirror surface formed on the inner peripheral surface of the collar can be completely transferred to the outer peripheral surface of the separating member 9 without being adversely affected by the release agent. On the other hand, in the method using the release agent, the product surface cannot be a mirror surface.

Further, the collar can be disposable after each molding, and in this case, it is possible to almost completely prevent the variation in the smoothness of the surface of the molded product among the molded products.

In the above-described embodiment, the separation mechanism adopting the method of feeding from the bottom of the bundle of sheets from the Nth sheet to the first sheet has been described as an example, but shown in FIG. As described above, the paper feed roll 8 is arranged on the upper side of the document path, the separating member 9 is arranged on the lower side of the document path, and paper is fed from the top of the bundle of sheets 2 from the first sheet to the Nth sheet. The present invention can be applied to a separating mechanism that employs.

[0033]

EFFECTS OF THE INVENTION By providing the surface of the separating member with a high smoothness such as a mirror finish, the pencil dust is less likely to be scraped when the original is separated, and stain marks are less likely to be left. As a result, the pencil original document itself is less contaminated, and the image read from the original document is not contaminated.
Further, since the surface of the separating member has a surface friction coefficient necessary for separating the document stack, a secondary obstacle such as double feeding and defective feeding does not occur.

[Brief description of the drawings]

FIG. 1 is a principle diagram showing an overall configuration of an automatic document feeder to which the present invention is applied.

FIG. 2 is an enlarged schematic view showing the vicinity of a sorting mechanism of the automatic document feeder shown in FIG.

FIG. 3 is an explanatory diagram for explaining a method of manufacturing a separating member of the separating mechanism.

FIG. 4 is a schematic view showing another example of the sorting mechanism.

[Explanation of symbols]

1 ... Platen glass, 2 ... Original, 3 ... Delivery roll,
4 ... feeding roll pressing member, 5 ... original document setting sensor,
6 ... Paper chute, 7 ... Separation mechanism, 8 ... Paper feed roll, 9
... Separation member, 10a, 10b ... Conveying roll pair, 11 ... Conveying belt device, 12 ... Paper chute, 13a, 13b ...
Transport roll pair, 14a, 14b ... Transport roll pair, 15 ...
Mold, 16 ... color

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Akira Kurimoto 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd.

Claims (4)

[Claims] 1. A sorting mechanism of an automatic document feeder, which sorts a plurality of documents one by one by feeding the documents between a sheet feeding roll and a sorting member pressed against the sheet feeding roll, wherein: The separating member is formed of a material based on polyurethane, has an coefficient of surface friction required for separating the original, and has a smooth surface such as a mirror finish. The sorting mechanism of the device. 2. The sorting mechanism of the automatic document feeder according to claim 1, wherein the surface roughness of the sorting member is 8 μm or less. 3. A sorting mechanism of an automatic document feeder for feeding a plurality of documents one by one by feeding the documents between a paper feed roll and a separating member pressed against the paper feed roll. In the method for manufacturing a separating member, the inside of a mold for forming the separating member is made of a material having water repellency and good releasability, and a color having an inner peripheral surface having a smoothness such as a mirror finish. A method of manufacturing a separating member used in a separating mechanism of an automatic document feeder, which is mounted and filled with a material based on polyurethane on the inside of the collar. 4. The material having water repellency and good releasability,
Rubber materials such as silicone rubber and fluororubber, resin materials such as polyolefin resin, polyacetal resin, polyamide resin, etc., or water repellent components such as silicone resin, silicone oil, fluorine resin, fluorine oil, etc. 2. A method of manufacturing a separating member used in a separating mechanism of an automatic document feeder according to claim 1, wherein the separating member is a resin material or a rubber material containing the.